Upward Angle Research Articles

Flume investigation of the influence of rigid barrier deflector angle on dry granular overflow mechanisms

Mass-wasting processes are often intercepted using rigid barriers, which are sometimes equipped with deflectors to prevent overspilling. Despite the engineering value of deflectors, they are currently only installed using empirical and prescriptive approaches because flow interaction mechanisms are not well understood. A 5 m flume was used to study dry granular flow deposition and overflow processes with and without deflectors of varying angles. The deflector angle was varied as 0°, 30°, 45°, and 60° with respect to the horizontal plane. For the geometric and material parameters adopted in this study, experimental results reveal that deflector angles greater than 45° develop steep ramp-like deadzones that result in effective energy dissipation as approaching flow impacts the deflector, whereas deflectors less than 45° rapidly develop shallow ramp-like deadzones, which promote high-energy overflow. Deflectors of at least 45° are required to develop upward overflow launch angles, whilst deflectors of 30° or less result in downward overflow launch angles. Upward launch angles indicate that a steep deadzone develops and effectively dissipates flow energy. An orthogonal deflector increases launch lengths by 40% compared to a bare rigid barrier.

Normal range of eye movement and its relationship to age

PurposeTo determine the range of eye movement in normal human subjects and to investigate the effect of age on eye movement.MethodsWe enrolled 261 healthy subjects, 5–91 years of age for this prospective observational study. Photographs were obtained in the cardinal gaze positions and processed using Photoshop. The processed images were analyzed using the Image J program to measure the angle of eye movement. The angle of eye movement was quantified using a modified limbus test. We measured the angle of eye movement in adduction, abduction, elevation, and depression.ResultsThe normal ranges of eye movement were 44.9 ± 7.2° in adduction, 44.2 ± 6.8° in adduction, 27.9 ± 7.6° in elevation, and 47.1 ± 8.0° in depression. There were significant negative correlations between the angles of horizontal and upward gazes and age (R = −0.294 in adduction, R = −0.355 in abduction, and R = −0.506 in elevation, all p < 0.001). However, the angle of downward gaze was not significantly correlated with age (R = 0.017, p = 0.722).ConclusionsThe normal ranges for the angle of horizontal gaze were symmetric, whereas the range of upward gaze angle was smaller than that for the downward gaze among all ages. Unlike the age‐related decline of range in other gazes, only downward gaze was not impaired by increasing age. Differences in eye‐movement range based on gaze direction and their associated aging mechanisms should be considered when assessing eye movements.

Nonlinear analysis of the crashworthy component of an eagle wave energy converter in rotating-collision

The Eagle wave energy converter (WEC) is novel device and has high power generation efficiency demonstrated by the small-scale model in the tank tests. During the sea trials of 10kW full-scale prototype performed from 2012 to 2014, a design problem occurred that the crashworthy component (namely End Beam) was crashed up by the rotor. In order to investigate the damage mechanism of End Beam and improve the design of the Eagle WEC, an impact analysis was conducted utilizing ANSYS/LS-DYNA. In the simulation, structures were modeled as full-scale parameters and assumed to be elastic–plastic. Meanwhile, the bottoms of End Beam were presumed to be standstill. Moreover, the influences of water surrounding the WEC structures were considered using added mass method. Through the simulation, the stress and strain distributions, collision force and the energy absorption of the system were obtained. The results fit well with the actual damage situation. Furthermore, three improvement schemes were proposed including enhancing the structure of End Beam, increasing the upward angle of the rotor and adding energy accumulator. The simulation results demonstrated that the third method can effectively absorb the kinetic energy of the rotor and prevent the WEC from destruction in the rough sea states.

Effect of heater orientation on pool boiling heat transfer from sintered copper microporous coating in saturated water

In this study, we investigate the heater orientation effects at inclination angles from 0° (horizontal upward) to 180° (horizontal downward) on pool boiling heat transfer of saturated water using a durable high-temperature thermally-conductive microporous coating (HTCMC) created by sintering copper powder of an average particle size of 67μm onto a 1cm×1cm plain copper surface with ∼300μm thickness. The HTCMC surface showed a critical heat flux (CHF) of ∼2MW/m2 and a maximum nucleate boiling heat transfer (NBHT) coefficient of ∼400kW/m2K, which are 2 and 8 times higher than those of a plain copper surface, respectively, at the upward horizontal inclination angle. The current experimental results showed that the CHF values of the HTCMC were maintained as ∼2MW/m2 at upward inclination angles from 0° to 90°, whereas the CHF values decreased as the inclination angle changed from 90o to 180o, at which point the values were ∼1.4MW/m2. The reduction at 180° is due to individual bubbles merging and forming larger bubbles by blockage from the surface. This increases the vapor residence time on the surface and prevents liquid access to the heated surface at downward inclination angles.However, it is noted that the CHF value of the HTCMC at 180° is ∼4.5 times higher than that of plain copper surface (0.3MW/m2 at 180°). HTCMC also shows a noticeably higher CHF value at 180° compared to nanocoating or other enhanced surfaces. This significant CHF enhancement is believed to be due to a large number of small feed jet bubbles created from porous structures, postponing the dryout caused by forming large bubbles on the heated surface.

Effect of upward angle on the drawing mechanism in longwall top-coal caving mining

• Gravity is the dominant factor while the upward angle has little influence on the drawing body's shape in LTCC.

Morphology study of thoracic transverse processes and its significance in pedicle-rib unit screw fixation.

Thoracic transverse process is an important anatomic structure of the spine. Several anatomic studies have investigated the adjacent structures of the thoracic transverse process. But there is still a blank on the morphology of the thoracic transverse processes. The purpose of the cadaveric study is to investigate the morphology of thoracic transverse processes and to provide morphology basis for the pedicle-rib unit (extrapedicular) screw fixation method. Forty-five adult dehydrated skeletons (T1-T10) were included in this study. The length, width, thickness, and the tilt angle (upward and backward) of the thoracic transverse process were measured. The data were then analyzed statistically. On the basis of the morphometric study, 5 fresh cadavers were used to place screws from transverse processes to the vertebral body in the thoracic spine, and then observed by the naked eye and on computed tomography scans. The lengths of thoracic transverse processes were between 16.63±1.59 and 18.10±1.95 mm; the longest was at T7, and the shortest was at T10. The widths of thoracic transverse processes were between 11.68±0.80 and 12.87±1.48 mm; the widest was at T3, and the narrowest was at T7. The thicknesses of thoracic transverse processes were between 7.86±1.24 and 10.78±1.35 mm; the thickest was at T1, and the thinnest was at T7. The upward tilt angles of thoracic transverse processes were between 24.9±3.1 and 3.0±1.56 degrees; the maximal upward tilt angle was at T1, and the minimal upward tilt angle was at T7. The upward tilt angles of T1 and T2 were obviously different from the other thoracic transverse processes (P<0.01). The backward tilt angles of thoracic transverse processes gradually increased from 24.5±2.91 degrees at T1 to 64.5±5.12 degrees at T10. The backward tilt angles were significantly different between each other, except between T5 and T6. In the validation study, screws were all placed successfully from transverse processes to the vertebrae of thoracic spine. The length, width, and thickness of the thoracic transverse processes are suitable for screw placement. And the obvious upward and backward tilt angles provide an excellent screw passage from transverse process to the vertebral body. Screw placement from the transverse processes to the vertebral body is feasible in the thoracic spine. However, there is still some place for improvement of the pedicle-rib unit screw fixation method.

An Investigation into the FertilizerParticle Dynamics Off-the-Disc

<abstract> <bold><sc>Abstract.</sc></bold> The particle size range specifications for two biosolids-derived organomineral fertilizers (OMF) known as OMF₁₀ (10:4:4) and OMF₁₅ (15:4:4) were established. Such specifications will enable field application of OMF with spinning disc systems using conventional tramlines spacing. A theoretical model was developed, which predicts the trajectory of individual fertilizer particles off-the-disc. The drag coefficient (C_d) was estimated for small time steps (10^-6 s) in the trajectory of the particle as a function of the Reynolds number. For the range of initial velocities (20 to 40 m s^-1), release angles (0° to 10°) and particle densities (1000 to 2000 kg m^-3) investigated, the analysis showed that OMF₁₀ and OMF₁₅ need to have particle diameters between 1.10 and 5.80 mm, and between 1.05 and 5.50 mm, respectively, to provide similar spreading performance to urea with particle size range of 1.00 to 5.25 mm in diameter. OMF₁₀ and OMF₁₅ should have 80% (by weight) of particles between 2.65 and 4.30 mm, and between 2.55 and 4.10 mm, respectively. Due to the physical properties of the material, disc designs and settings that enable working at a specified bout width by providing a small upward particle trajectory angle (e.g., 10°) are preferred to high rotational velocities. However, field application of OMF with spinning discs applicators may be restricted to tramlines spaced at a maximum of 24 m; particularly, when some degree of overlapping is required between two adjacent bouts. The performance of granular fertilizers can be predicted based on properties of the material, such as particle density and size range, using the contour plots developed in this study.

Enhancing the reproducibility of ocular vestibular evoked myogenic potentials by use of a visual target originating from a head-mounted laser.

Ocular vestibular evoked myogenic potentials (oVEMPs) represent extraocular muscle activity in response to vestibular stimulation. oVEMP amplitudes are known to increase with increasing upward gaze angle, while the patient fixates a visual target. We investigated two different methods of presenting a visual target during oVEMP recordings. 57 healthy subjects were enrolled in this study. oVEMPs were elicited by 500 Hz air-conducted tone bursts while the subjects were looking upward at a marking which was either fixed on the wall or originated from a head-mounted laser attached to a headband, in either case corresponding to a 35° upward gaze angle. oVEMP amplitudes and latencies did not differ between the subjects looking at the fixed marking and the ones looking at the laser marking. The intra-individual standard deviation of amplitudes obtained by two separate measurements for each subject, however, as a measure of test-retest reliability, was significantly smaller for the laser headband group (0.60) in comparison to the group looking at the fixed marking (0.96; p = 0.007). The intraclass correlation coefficient revealed better test-retest reliability for oVEMP amplitudes when using the laser headband (0.957) than using the fixed marking (0.908). Hence, the use of a visual target originating from a headband enhances the reproducibility of oVEMPs. This might be due to the fact that the laser headband ensures a constant gaze angle and rules out the influence of small involuntary head movements on the gaze angle.

Droplet Spectrum Analysis from Artificially Generated Rain Showers

Severe droughts were experienced by many southerly states of the Indian subcontinent during the past decade. Farmer suicides were reported from the state of Andhra Pradesh year after year, especially when the monsoons failed. The government of India conducted expensive rain enhancement experiments through artificial cloud seeding; this did happen, but at enormous infrastructural costs and organizational endeavors. In this paper, the attempt is to find alternative shower generation mechanisms at the scale of an individual cropland. The application of a new rain simulator is explored. The crux of the problem lies in generating showers with drops that not only fall with approximately the same speeds as the natural rain showers but also have matching drop size distributions. Previous simulators have not looked at this aspect; none have attempted to recreate a drop size spectrum that is indistinguishable from natural rain showers. This is the paper’s mainstay; new calculations are shown for a uniquely fabricated rain simulator that allows tridirectional maneuverability with regard to the spraying geometry. Only when the nozzle placed at 2.5 m from the ground is tilted at an upward angle of 80° with respect to the boom’s horizontal axis, a resultant spectrum is obtained that closely matches the northeast monsoon shower spectra at optimal crosswind speeds. In contrast, when the spray nozzles point vertically downwards, as in sprinklers, the resultant droplet spectra do not match real rain shower spectra; the number concentrations of both large and small droplets are overpredicted with fall velocities grossly higher than their terminal velocities. The droplet energy flux obtained from a vertically downward tilted nozzle reach the highest value of 24 W·m−2. On the contrary, the maximum energy flux value from a skyward projected shower slides down to 2.0 W·m−2 matching fluxes for natural rainfall.

The Effects of Commonly Used Upward Gaze Angles on Ocular Vestibular Evoked Myogenic Potentials

Ocular vestibular evoked myogenic potentials (oVEMP) represent extraocular muscle activity in response to vestibular stimulation. oVEMP amplitudes are known to be modulated by gaze elevation. However, it is not well known to which extent oVEMP are modulated by upward gaze. We thus investigated the effects of commonly used upward gaze angles on oVEMP amplitudes and latencies. Prospective study. Tertiary referral center for vestibular disorders. Thirty-two healthy subjects were enrolled in this study. 500 Hz air-conducted tone bursts were used to elicit oVEMP with the subject maintaining 30 and 35 degrees and maximal upward gaze, respectively. Amplitudes and latencies of oVEMP responses. n1-p1 amplitudes significantly increased with increasing gaze angle from 30 to 35 degrees. Maximal up-gaze, however, did not result in further enlargement of amplitudes. Latencies were not affected by gaze elevation. A small increase in upward gaze angle caused a considerable augmentation of amplitudes. Controlling the level of gaze when recording oVEMP is thus indispensable to ensure interindividual and intraindividual comparability of oVEMP results.

Effects of Immersion Depth on Flow Turbulence of Liquid Steel in a Slab Mold Using a Nozzle with Upward Angle Rectangular Ports

techniques including tracer injection, particle image velocimetry and ultrasound velocimetry. Fluid dynamics near the ports indicate that the discharging jet is subdivided into upper and lower jets when the SEN is at its deep position (185 mm) forming a double roll flow (DRF). At the shallow position (115 mm) the tendency to form two jets decrease with a general trend to form a single jet and a single roll flow (SRF) pattern. These flows are attributed to the difference of the hydrostatic pressures between both submergences. Both, the upper flow in the DRF and the upper flow in the SRF induce free shear flows near the free bath surface that give origin to vortexes and unstable meniscus dynamics. Therefore, nozzle ports with upward angles create small pressure gradients which, in spite of their small magnitudes, have profound effects on fluid flow patterns of the fluid in the whole working mold volume. The results indicate that this nozzle works with less turbulence in the shallow position.

Laryngeal mask airway exchange using a gum elastic bougie with a rotational twist technique.

Previous studies have sought to determine the feasibility of exchanging the laryngeal mask airway (LMA) for an endotracheal tube (ETT) over a gum elastic bougie (GEB) and found the practice to have a success rate of about 50%. It has been speculated that the poor success rate may be due to the upward angle of the bougie tip meeting resistance against the anterior laryngeal wall. The use of a 90- to 180-degree twist technique to angle the bougie tip away from the anterior tracheal wall and caudally along the trachea theoretically could improve results. We conducted a prospective cadaveric study to determine if the use of a bougie 90- to 180-degree twist technique or the use of a more flexible pediatric bougie would improve previously published success rates. Emergency medicine personnel attempted exchange of an LMA for an ETT over a GEB using a twisting technique. Despite using the twisting technique, successful exchange over a bougie remained at 50%, similar to previous studies. Using a smaller, more flexible pediatric bougie led to a successful exchange in only 28% of attempts. In this study, the adding of a twist technique or using a pediatric bougie did not result in consistent successful exchange to an ETT from an LMA.

Improvement of steel billet cleanliness and thermal responses of multiple strands through fluid flow control

Fluid flow of liquid steel in a six-strand billet tundish using a simple squared advanced pouring box (APB) promotes the formation of heavy skulls, particularly in the corners of the vessel, and heterogeneous product cleanliness and thermal responses in the strands. To improve the flow patterns, two other APBs were designed and tested through water model tracer injection techniques, ultrasound velocimetry and mathematical simulations. The first APB is the actual design. The second APB maintains the same geometry but is equipped with two circular orifices with zero angle respect to the horizontal at each lateral side placed toward the tundish back wall. The third APB geometry is also squared with elliptic orifices with double upward angles also oriented to the tundish back wall. The first two devices induce long shearing–circulating flows, leaving stagnant regions inside the fluid bulk and particularly in the four upper corners of the tundish, which explains the existence of skulls in the actual tundish. The third device provides a long recirculating flow that eliminates all stagnant regions. Mathematical simulations have indicated that this flow carries energy, through convection mechanisms, toward the upper bath surface, indicating the elimination of skulls. Trials at the caster proved that all skulling problems were eliminated, and thermal and metallurgical evenness was reached using this simple flow control device.

Effect of a Polymer Additive on Heat Transfer and Pressure Drop Behaviors of Upward Air–Water Flow in an Inclined Smooth Circular Tube

This article presents an experimental study of the effect of polyacrylamide (PAM) on heat transfer and frictional pressure drop behaviors of upward air–water two-phase flow in an inclined smooth circular tube with an upward inclination angle of 8 degrees from the horizontal direction. The test tube has an inside diameter of 40 mm and an outside diameter of 48 mm. A PAM water solution with a concentration of 300 ppm was used in the experiments. The liquid phase superficial velocities are 0.52, 1.02, and 1.46 m/s and the gas-phase superficial velocities are from 1.79 to 6.54 m/s. Heat transfer tests were performed by cooling the air–water flow inside the test tube through its wall using the cooling water with a heat transfer length of 3 m, and two-phase pressure drops were measured over a length of 3.1 m. Results show that the air–water two-phase frictional pressure drops can be reduced from 26.2% to 42.7%, while the two-phase heat transfer coefficients can be reduced from 39.7% to 80.8% with addition of PAM. Furthermore, new proposed physical mechanisms of the two-phase frictional pressure drop and heat transfer reductions are used to explain the experimental results.

Analysis of risk factors for dry eye syndrome in visual display terminal workers

To analyze the risk factors for dry eye syndrome in visual display terminal (VDT) workers and to provide a scientific basis for protecting the eye health of VDT workers. Questionnaire survey, Schirmer I test, tear break-up time test, and workshop microenvironment evaluation were performed in 185 VDT workers. Multivariate logistic regression analysis was performed to determine the risk factors for dry eye syndrome in VDT workers after adjustment for confounding factors. In the logistic regression model, the regression coefficients of daily mean time of exposure to screen, daily mean time of watching TV, parallel screen-eye angle, upward screen-eye angle, eye-screen distance of less than 20 cm, irregular breaks during screen-exposed work, age, and female gender on the results of Schirmer I test were 0.153, 0.548, 0.400, 0.796, 0.234, 0.516, 0.559, and -0.685, respectively; the regression coefficients of daily mean time of exposure to screen, parallel screen-eye angle, upward screen-eye angle, age, working years, and female gender on tear break-up time were 0.021, 0.625, 2.652, 0.749, 0.403, and 1.481, respectively. Daily mean time of exposure to screen, daily mean time of watching TV, parallel screen-eye angle, upward screen-eye angle, eye-screen distance of less than 20 cm, irregular breaks during screen-exposed work, age, and working years are risk factors for dry eye syndrome in VDT workers.

Extension of application field of analytical formulas for the computation of projectile motion in midair

The classic problem of the motion of a point mass (projectile) thrown at an angle to the horizon is reviewed. The air drag force is taken into account with the drag factor assumed to be constant. An analytical approach is used for the investigation. Application field of the previously obtained approximate analytical formulas has been expanded both in the upward launch angle and in the direction of increase of the initial speed of the projectile. The motion of a baseball is presented as an example. It is shown that in a sufficiently wide ranges of initial velocity and launch angle the relative error in calculating the distance of the ball does not exceed 1%.

Feasibility Investigation of Obstacle-Avoiding Sensors Unit without Image Processing

Feasibility of a simple method to detect step height, slope angle, and trench width using four infrared-light-source PSD range sensors is examined, and the reproducibility and accuracy of characteristic parameter detection are also examined. Detection error of upward slope angle is within 2.5 degrees, while it is shown that the detection error of downward slope angle exceeding 20 degrees is very large. In order to reduce such errors, a method to improve range-voltage performance of a range sensor is proposed, and its availability is demonstrated. We also show that increase in trial frequency is a better way, although so as not to increase the detection delay. Step height is identified with an error of ±1.5 mm. It is shown that trench width cannot be reliably measured at this time. It is suggested that an additional method is needed if we have to advance the field of obstacle detection.

Description of a transosseous approach to the L5-S1 disc and 2 clinical case reports

BackgroundThe lumbosacral disc with the adjacent iliac crest and its relationships to neurologic, visceral, and vascular structures is difficult to approach with cannula-based retractor systems. Previous, less invasive approaches have been described to access this space. Anterior, presacral, and transforaminal approaches each have approach-related complications that have prevented their widespread adoption. A laterally based approach to this disc between the exiting L5 nerve root and traversing S1 nerve root would theoretically eliminate visceral and vascular complications but would necessarily course through the adjacent iliac crest. Our objective was to determine the feasibility of placing an interbody device into the L5-S1 disc space through a lateral transosseous approach. MethodsSix transosseous pathways were created from the iliac crest, laterally through the sacral ala, and entering the L5-S1 intervertebral disc space (3 cadavers). The positions of the portals in relation to the local anatomy were evaluated anatomically and with computed tomographic sagittal, coronal, and axial planes. We measured the lengths, heights, and widths of the pathways; distance between the L5 and S1 nerve roots; endplate diameters; and angles necessary to access the space. In addition, 2 clinical cases using the transosseous pathway are presented. ResultsComputed tomographic scans and anatomic evaluations showed that there was an average 22-mm distance between the L5 and S1 nerve roots available to enter the L5-S1 disc space. The mean length of the pathway was 69 mm, and the mean height was 27 mm. The mean angle of the approach was 45° off the posterior-anterior axis, and there was a 25° upward angle from true lateral in the frontal plane. ConclusionsA lateral, transosseous approach to the L5-S1 disc space for placing an interbody device is feasible. A closed cannula-based technique may offer reduced approach-related complications. Further studies will be required to determine the reproducibility and utility of this pathway.

Trial history biases the spatial programming of antisaccades

The historical context in which saccades are made influences their latency and error rates, but less is known about how context influences their spatial parameters. We recently described a novel spatial bias for antisaccades, in which the endpoints of these responses deviate towards alternative goal locations used in the same experimental block, and showed that expectancy (prior probability) is at least partly responsible for this 'alternate-goal bias'. In this report we asked whether trial history also plays a role. Subjects performed antisaccades to a stimulus randomly located on the horizontal meridian, on a 40° angle downwards from the horizontal meridian, or on a 40° upward angle, with all three locations equally probable on any given trial. We found that the endpoints of antisaccades were significantly displaced towards the goal location of not only the immediately preceding trial (n-1) but also the penultimate (n-2) trial. Furthermore, this bias was mainly present for antisaccades with a short latency of <250ms and was rapidly corrected by secondary saccades. We conclude that the location of recent antisaccades biases the spatial programming of upcoming antisaccades, that this historical effect persists over many seconds, and that it influences mainly rapidly generated eye movements. Because corrective saccades eliminate the historical bias, we suggest that the bias arises in processes generating the response vector, rather than processes generating the perceptual estimate of goal location.

Determination of Minimum Effective Height of Transparent Radiation Face Shielding for Fluoroscopy

During interventional procedures, the vast majority of scatter radiation originates from the patient and table and travels in all directions in straight lines. Because the operator's head is much higher than the patient and at an angle upward and to the side of the patient (not directly above), the scatter received by the operator's head is projected in an upward angle. Thus a face shield could potentially be lower than the object it is shielding, e.g., below the eyes. This principle may be used as an advantage to design the lowest shield that effectively protects the head while providing optimum vision, appearance, acoustics, low weight, and sense of openness. A flat acrylic plate shield, 0.5 mm Pb equivalence, was suspended vertically in front of a 451P dosimeter. A phantom patient created scatter in an interventional suite while the dosimeter was placed at the level of the crowns of different operators' heads. Many different configurations were tested to determine which ones would provide effective shielding. The results confirmed that the top of the shield may reside several centimeters below the vertical height of the dosimeter (operator's crown), allowing line of sight to monitor above the shield, and still provide effective shielding equivalent to when the dosimeter is positioned directly behind the center of the shield. The image receptor functioned as an effective shield against scatter. Factors increasing the minimum height of effective shielding included shorter operator, opposite oblique projection of image receptor, and shield closer to the face (in horizontal direction).